The present disclosure relates to a fixing device to fix a toner image on a sheet and an image forming apparatus including the fixing device.
In an image forming apparatus, a toner image formed on a surface of an image carrier is transferred on a sheet and then heated and pressed by a fixing device to be fixed on the sheet.
A fixing method of the fixing device includes a sliding type fixing method in which an endless fixing belt is driven by a pressing roller to be rotated. In the sliding type fixing method, the fixing belt is pressed to the pressing roller by a pushing pad. When a temperature detection position of the fixing belt is different from a heated position of the fixing belt by a heater, such as an IH heater, in a rotation direction of the fixing belt, if the rotation of the fixing belt is stopped, it becomes impossible to detect a temperature of the fixing belt, and an abnormal heat generation may occur. Then, for safety measure, the sliding type fixing device is provided with a rotation detection mechanism to detect the rotation of the fixing belt. The rotation detection mechanism detects a rotation of a cap which covers an end portion of the fixing belt and rotates together with the fixing belt. Between the fixing belt and the cap, an elastic member having a high friction coefficient is arranged so as to transfer the rotation of the fixing belt to the cap.
On the other hand, between the fixing belt and the pushing pad, in order to reduce a sliding load generated between the fixing belt and the pushing pad, a lubricant having a relatively low viscosity is applied. If the lubricant is flowed out from an inner circumferential face of the fixing belt and adheres to the elastic member, the elastic member is slipped, and the rotation of the fixing belt may not be transferred to the cap. Then, it is required to control the flow of the leaked lubricant.
Then, an elastic member may be provided, which thermally expands to come into contact with the inner circumferential face of the fixing belt and blocks the lubricant.
However, depending on a thermally expanded degree of the elastic member, the elastic member does not always come into contact with the inner circumferential face of the fixing belt. Additionally, because it is required to add a new member and to cause an increase in cost.